Vacuum Processing Gas Distribution Uniformity
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Solution Overview
Problem
Conventional vacuum processing apparatuses for semiconductor wafers face challenges in achieving uniform gas distribution and plasma density, leading to nonuniform processing results due to the difficulty in creating an axisymmetrical gas concentration distribution on the wafer surface.
Innovation Solution
A vacuum processing apparatus with a gas diffusion ring and a ring cover that introduces processing gases from different locations, including the inner peripheral sidewall and outer periphery, to achieve a uniform gas distribution and plasma density, using a combination of first and second mixed gases with varying compositions and flow rates to enhance processing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If processing gases are introduced from multiple locations to achieve uniform gas distribution, then processing uniformity is improved, but device complexity increases
Solution Approach 1:
The gas introduction system is segmented into multiple independent gas introduction holes positioned at different locations (central axis and outer periphery) in the processing chamber wall. Each hole can introduce processing gas independently, allowing separate control of gas flow to different regions of the wafer surface, thereby achieving uniform gas distribution without requiring a single complex gas introduction mechanism.
Solution Approach 2:
Gas introduction holes are asymmetrically positioned at both the central axis and outer periphery of the processing chamber, rather than using a symmetric single-point introduction. This asymmetric multi-location configuration enables differential gas distribution to compensate for radial temperature variations and reaction product accumulation, achieving uniform processing across the wafer surface.
2Manufacturing precision
If gas concentration distribution is made uniform across the chamber, then processing uniformity improves, but ability to compensate for radial temperature variations is reduced
Solution Approach 1:
Different regions of the processing chamber are provided with different gas concentration characteristics through strategically positioned gas introduction holes. The outer periphery holes compensate for temperature-induced gas accumulation by introducing additional processing gas to that region, while the central axis holes maintain appropriate gas concentration at the center. This local quality adjustment achieves overall processing uniformity while adapting to radial temperature variations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus ensures uniform processing performance across the semiconductor wafer surface by regulating gas concentration distribution, reducing radial and circumferential nonuniformity, and maintaining axisymmetrical plasma density, thereby improving processing accuracy and yield.
Implementation Method 1
an electric field is supplied from outside the vacuum vessel to a reactive gas introduced into the processing chamber to turn it into a plasma
Implementation Method 2
an electric field is supplied from outside the vacuum vessel to a reactive gas introduced into the processing chamber
Implementation Method 3
the gas concentration distribution is flattened due to gas diffusion
Data Source
AI summary
The invention provides a plasma processing apparatus for processing a wafer mounted on a sample stage placed in a vacuum processing chamber using a plasma generated in the vacuum chamber. The plasma processing apparatus comprises a plate placed in the vacuum processing vessel above and opposed to the wafer, the plate having a through hole through which a first processing gas is introduced; a first and second cylindrical member arranged vertically and adjacently; and means communicating with the gap between the first and second cylindrical member for supplying a second processing gas. The wafer is processed while the first processing gas and the second processing gas having different compositions are supplied.